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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* windows.c: Routines to deal with register window management |
3 | * at the C-code level. | |
4 | * | |
5 | * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu) | |
6 | */ | |
7 | ||
8 | #include <linux/kernel.h> | |
9 | #include <linux/sched.h> | |
10 | #include <linux/string.h> | |
11 | #include <linux/mm.h> | |
12 | #include <linux/smp.h> | |
1da177e4 | 13 | |
7c8ee361 | 14 | #include <asm/cacheflush.h> |
7c0f6ba6 | 15 | #include <linux/uaccess.h> |
1da177e4 | 16 | |
7c8ee361 SR |
17 | #include "kernel.h" |
18 | ||
1da177e4 LT |
19 | /* Do save's until all user register windows are out of the cpu. */ |
20 | void flush_user_windows(void) | |
21 | { | |
22 | register int ctr asm("g5"); | |
23 | ||
24 | ctr = 0; | |
25 | __asm__ __volatile__( | |
26 | "\n1:\n\t" | |
27 | "ld [%%g6 + %2], %%g4\n\t" | |
28 | "orcc %%g0, %%g4, %%g0\n\t" | |
29 | "add %0, 1, %0\n\t" | |
30 | "bne 1b\n\t" | |
31 | " save %%sp, -64, %%sp\n" | |
32 | "2:\n\t" | |
33 | "subcc %0, 1, %0\n\t" | |
34 | "bne 2b\n\t" | |
35 | " restore %%g0, %%g0, %%g0\n" | |
36 | : "=&r" (ctr) | |
37 | : "0" (ctr), | |
38 | "i" ((const unsigned long)TI_UWINMASK) | |
39 | : "g4", "cc"); | |
40 | } | |
41 | ||
42 | static inline void shift_window_buffer(int first_win, int last_win, struct thread_info *tp) | |
43 | { | |
44 | int i; | |
45 | ||
46 | for(i = first_win; i < last_win; i++) { | |
47 | tp->rwbuf_stkptrs[i] = tp->rwbuf_stkptrs[i+1]; | |
4d7b92ad | 48 | memcpy(&tp->reg_window[i], &tp->reg_window[i+1], sizeof(struct reg_window32)); |
1da177e4 LT |
49 | } |
50 | } | |
51 | ||
52 | /* Place as many of the user's current register windows | |
53 | * on the stack that we can. Even if the %sp is unaligned | |
54 | * we still copy the window there, the only case that we don't | |
55 | * succeed is if the %sp points to a bum mapping altogether. | |
56 | * setup_frame() and do_sigreturn() use this before shifting | |
57 | * the user stack around. Future instruction and hardware | |
58 | * bug workaround routines will need this functionality as | |
59 | * well. | |
60 | */ | |
61 | void synchronize_user_stack(void) | |
62 | { | |
63 | struct thread_info *tp = current_thread_info(); | |
64 | int window; | |
65 | ||
66 | flush_user_windows(); | |
67 | if(!tp->w_saved) | |
68 | return; | |
69 | ||
70 | /* Ok, there is some dirty work to do. */ | |
71 | for(window = tp->w_saved - 1; window >= 0; window--) { | |
72 | unsigned long sp = tp->rwbuf_stkptrs[window]; | |
73 | ||
74 | /* Ok, let it rip. */ | |
75 | if (copy_to_user((char __user *) sp, &tp->reg_window[window], | |
4d7b92ad | 76 | sizeof(struct reg_window32))) |
1da177e4 LT |
77 | continue; |
78 | ||
79 | shift_window_buffer(window, tp->w_saved - 1, tp); | |
80 | tp->w_saved--; | |
81 | } | |
82 | } | |
83 | ||
84 | #if 0 | |
85 | /* An optimization. */ | |
86 | static inline void copy_aligned_window(void *dest, const void *src) | |
87 | { | |
88 | __asm__ __volatile__("ldd [%1], %%g2\n\t" | |
89 | "ldd [%1 + 0x8], %%g4\n\t" | |
90 | "std %%g2, [%0]\n\t" | |
91 | "std %%g4, [%0 + 0x8]\n\t" | |
92 | "ldd [%1 + 0x10], %%g2\n\t" | |
93 | "ldd [%1 + 0x18], %%g4\n\t" | |
94 | "std %%g2, [%0 + 0x10]\n\t" | |
95 | "std %%g4, [%0 + 0x18]\n\t" | |
96 | "ldd [%1 + 0x20], %%g2\n\t" | |
97 | "ldd [%1 + 0x28], %%g4\n\t" | |
98 | "std %%g2, [%0 + 0x20]\n\t" | |
99 | "std %%g4, [%0 + 0x28]\n\t" | |
100 | "ldd [%1 + 0x30], %%g2\n\t" | |
101 | "ldd [%1 + 0x38], %%g4\n\t" | |
102 | "std %%g2, [%0 + 0x30]\n\t" | |
103 | "std %%g4, [%0 + 0x38]\n\t" : : | |
104 | "r" (dest), "r" (src) : | |
105 | "g2", "g3", "g4", "g5"); | |
106 | } | |
107 | #endif | |
108 | ||
109 | /* Try to push the windows in a threads window buffer to the | |
110 | * user stack. Unaligned %sp's are not allowed here. | |
111 | */ | |
112 | ||
113 | void try_to_clear_window_buffer(struct pt_regs *regs, int who) | |
114 | { | |
115 | struct thread_info *tp = current_thread_info(); | |
116 | int window; | |
117 | ||
1da177e4 LT |
118 | flush_user_windows(); |
119 | for(window = 0; window < tp->w_saved; window++) { | |
120 | unsigned long sp = tp->rwbuf_stkptrs[window]; | |
121 | ||
122 | if ((sp & 7) || | |
123 | copy_to_user((char __user *) sp, &tp->reg_window[window], | |
acce3faf | 124 | sizeof(struct reg_window32))) { |
3d8098eb | 125 | force_exit_sig(SIGILL); |
acce3faf EB |
126 | return; |
127 | } | |
1da177e4 LT |
128 | } |
129 | tp->w_saved = 0; | |
1da177e4 | 130 | } |